The reason I mention bodkins is that I learned this week that Sir Isaac Newton, considered by many to have been an intelligent man, spent some time in the 1660s sticking one into his eye. On purpose.

Newton was famously interested in optics and the nature of light. However, he was also interested in the visual stimulus, and the physiological processes by which objective reality is perceived by us.

So, to address this question, Sir Isaac Newton thought it would be sensible to start poking himself in the eye with a large needle. We know this because, like any good scientist, Isaac Newton left detailed experimental notebooks. He even included helpful illustrations.

And therein, perhaps, lies the difference between the dedicated scientist and the layperson. It would take a great deal of persuasion to get a normal person to poke themselves in the eye with a needle – Isaac Newton did it because he hoped he might learn something about color.

And did he? Well, sort of. He learned that, when you poke yourself in the eye, you disrupt your vision. When he stuck the bodkin between his eyeball and his eye socket, “as neare to backside of my eye as I could”, then he saw spots. Those spots were clearest “when I continued to rub my eye [with the] point of bodkine”.